Brain aneurysms are a high risk condition in which bulging blood vessels in the brain are at risk of rupture. The mortality rate after rupture is 30-60% if no treatment is administered. Current treatment for both ruptured and unruptured aneurysms includes surgical clipping (exovascular therapy) and catheter based intervention (endovascular therapy). The latter, which is the focus of this work, places platinum coils into the aneurysm to induce clotting and sequestration of the aneurysm. The primary challenge associated with endovascular aneurysm therapy is the risk of aneurysm recurrence due to mechanical compaction and enzymatic digestion of the clot in the aneurysm sac. This proposal will produce a novel, cost-effective, clinically translatable strategy to improve the outcome of endovascular coiling of intracranial aneurysms. We posit that sustained release of naturally-occurring crosslinking agents delivered from coated endovascular coils will increase the mechanical stiffness of the clots and reduce fibrinolysis. Stabilized clots will be resistant to failure modes associated with coil compaction and enzymatic degradation. This approach will be validated in vitro during this project. Research activities will focus on characterizing the dosing and release of bioactive crosslinking agent from polymeric coatings. In vitro efficacy will be demonstrated using a model aneurysm sac under flow of whole blood. The results from this project will be used to define specific formulations and dosing ranges for use in prospective in vivo experiments using a canine pouch model for intracranial aneurysms. Pre-clinical studies will establish safety and efficacy of drug eluting embolization coils. This technology has the potential to dramatically improve outcomes related to coil embolization of intracranial aneurysms.